SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '528723fdda2ad953e4a17fe63abea9138f6879dcf84c9ca9f33e580425f5807c' 
  AND token = 'rTE1U3CwUae+8NrrrSshSqIoIxqehOOAa/WFf3RQQ98=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}